There are required varieties and practices for growing corn intended for direct human consumption (i.e. making cornmeal or breakfast cereal).
Most corn though goes to animal feed, industrial uses (corn starch, syrup, etc), or export.
(source: am a 5th generation corn farmer)
The main differences are days to maturity, resistances to a variety of things, and nutrition content.
There are required varieties and practices for growing corn intended for direct human consumption (i.e. making cornmeal or breakfast cereal).
Most corn though goes to animal feed, industrial uses (corn starch, syrup, etc), or export.
(source: am a 5th generation corn farmer)